Device and method for the automatic counting of medical gauze

Abstract

Provided is a device and method for the automatic counting of medical gauze, which can automatically count the number of medical gauzes used for absorbing blood and other body fluids generated during surgical operations. This device includes a container, which collects the gauze containing radiopaque markers; a support, which supports the container; a radiographic unit, which radiographs the container at various angles using X-ray; a controller, which receives radiographic information from the container and counts the total number of markers in the container using radiographic information; and a display, which operates the system and displays the number of markers calculated by the controller.

What is claimed is: 
     
       1. A device for counting medical gauze automatically, comprising:
 a container to collect gauze embedded with radiopaque markers; 
 a support, which supports the container; 
 a radiographic unit, which radiographs the container at various angles using X-ray; 
 a controller, which receives information from the radiographic unit and counts the total number of markers in the container using such radiographic information; and 
 a display, which controls the unit and displays the number of the markers calculated by the controller, wherein the controller calculates the X-ray attenuation coefficients at every position within the pre-specified three-dimensional (3-D) space encompassing the container by performing a tomographic reconstruction using the radiographs taken at various angles, thus preventing errors in gauze counting potentially caused by superimposed markers in the projection X-ray images. 
 
     
     
       2. The device of  claim 1 , wherein the container comprises a dome-shaped plate dividing the internal space of the container into an upper and a lower space, and such dividing plate contains numerous holes through which blood absorbed by the gauze drains from the upper space into the lower space. 
     
     
       3. The device of  claim 1 , further comprising mechanical means of moving the support such that the supported container is moved relative to the detector and x-ray tube. 
     
     
       4. The device of  claim 1 , wherein a calibration unit is fixed to the radiographic unit, and
 the calibration unit comprises: 
 a frame, which is fixed to the radiographic unit to enclose the container; 
 a background material, which is fixed to the frame and has an X-ray transmittance similar to that of blood; and 
 a calibration marker, which is fixed to a center portion of the background material and has the same X-ray transmittance as that of the radiopaque marker. 
 
     
     
       5. The device of  claim 4 , wherein the controller calculates the contrast ratio between the background material and the calibration marker and stops the subsequent processes if the calibration marker is not included in an image or the contrast ratio is less than the predetermined value. 
     
     
       6. The device of  claim 1 , wherein the controller compares the calculated number of gauzes with the number of gauzes input by the user, then determines whether the numbers are in agreement with each other. 
     
     
       7. The device of  claim 1 , wherein the marker is fixed in cloth that is affixed to the gauze and formed into a spherical shape, and the cloth has a thickness of 1 mm or more. 
     
     
       8. The device of  claim 1 , wherein the radiographic unit comprises:
 multiple arms, which are coupled to a supporting pillar buttressing the support; 
 multiple installing parts, which are each fixed to one end of the numerous arms; 
 multiple X-ray tubes, each of which are fixed to the end of an installing part so as to irradiate X-ray to the container; and 
 multiple detectors, each of which are fixed to the opposite ends of the numerous arms so as to detect the X-ray passing through the container, then transfer the detected information to the controller. 
 
     
     
       9. The device of  claim 1 , wherein if markers of varying sizes are combined in the container, the controller calculates the number of markers according to the sizes thereof, and the display indicates the number of markers according to size. 
     
     
       10. The device of  claim 1 , wherein the controller separates the image pixels of tomographically reconstructed image data of markers from those of other materials by comparing the X-ray attenuation coefficients of each pixel to the known attenuation coefficient of the reference marker material, thereby selecting those pixels with attenuation coefficients falling within the accepted range of standard deviation, and further segments those separated image pixels to the individual spatially connected objects. 
     
     
       11. The device of  claim 10 , wherein the controller removes other object pixels from the list of candidate objects to be counted by examining the sphericalness of the object and uniformity of attenuation coefficients within the object. 
     
     
       12. The device of  claim 10 , wherein the controller categorizes the objects into different marker types by comparing the measured size of each segmented object with previously determined sizes of reference marker types. 
     
     
       13. A method for counting medical gauze automatically, comprising:
 radiographing the container, which collects the gauze embedded with radiopaque markers, using X-ray; 
 calculating the number of markers in the container using information obtained from radiographing the container; and 
 displaying the calculated number of markers, wherein the calculation of the number of markers in the container comprises: 
 performing a tomographic reconstruction of a plurality of radiographs taken at various angles to calculate X-ray attenuation coefficients at each point within a pre-specified three-dimensional (3-D) space encompassing the container; 
 separating the pixels of the tomographically reconstructed image data of the marker from those of gauzes and other materials by comparing the X-ray attenuation coefficients of each pixel to the known attenuation coefficient of the reference marker material, and further segmenting those separated image pixels into individual spatially connected objects; 
 classifying the segmented objects in the reconstructed tomographic images into different marker types by comparing the measured size of each segmented object with the previously determined sizes of reference marker types; and 
 counting the classified markers for each type. 
 
     
     
       14. The method of  claim 13 , wherein the radiographing of the container comprises:
 irradiating the container with X-ray; and 
 detecting the X-ray passed through the container, wherein the irradiation and X-ray detection are performed multiple times sequentially. 
 
     
     
       15. The method of  claim 13 , wherein the radiographing of the container comprises:
 irradiating the container with X-ray; and 
 detecting the X-ray passed through the container, wherein the irradiation and X-ray detection are performed multiple times simultaneously. 
 
     
     
       16. The method of  claim 13 , further comprising a calibration process before or during the radiographing of the container and the calculation of the number of the markers in the container,
 wherein the calibration process comprises: 
 obtaining radiographic images of the container and the calibration unit, located outside of the container but within the projected field of the detector(s), testing if the calibration unit is included in all images and testing if the calibration markers and background materials have the same x-ray attenuation characteristics as the radiopaque markers and blood soaked surgical gauzes, respectively, which is necessary for the controller to determine whether the radiographic unit and container are in correct alignment and to determine whether exposure of x-ray tube is adequate for the next step of the calculation process; 
 determining whether the calibration markers are included in the radiographed image and whether the contrast ratio between the background material and the calibration markers is less than a predetermined value; and 
 halting subsequent processes if any of the calibration markers are not included in the radiographed image, or if the contrast ratio between the background material and the calibration markers is less than the predetermined value. 
 
     
     
       17. The method of  claim 13 , wherein calculating the number of the markers in the container, the number of gauzes input by the user is compared with the number of markers, and it is then determined whether the numbers are in agreement with each other; and in displaying the total calculated number of markers, such display includes the number of gauzes input by the user, the number of markers, and whether both numbers are in agreement with each other. 
     
     
       18. The method of  claim 13 , wherein if markers of different sizes are combined in the container, the number of markers is calculated and totals are displayed according to marker size. 
     
     
       19. The method of  claim 13 , wherein the objects consisting of non-marker solid materials with high attenuation coefficients are removed from the list of candidate markers to be counted by examining the sphericalness of the object and uniformity of attenuation coefficients within the object.